<!DOCTYPE html>
<html lang="en" xml:lang="en"> 
<head>
    <title>Backup/Restore Configuration</title>
    <meta charset="UTF-8" />

    <style>
        h1 {font-size: 2em;}
        h2 {font-size: 1.5em; margin-block-start: 0.0em; margin-block-end: 0.2em;}
        h3 {font-size: 1.2em;}
        p {font-size: 1em;}

        input[type=number] {
            width: 138px;
            padding: 10px 5px;
            display: inline-block;
            border: 1px solid #ccc;
            font-size: 16px; 
        }

        .button {
            padding: 5px 10px;
            width: 205px;
            font-size: 16px;
        }
    </style>

</head>

<body style="font-family: arial; padding: 0px 10px;">
    <h2>Backup Configuration</h2>
    <p>With the following action the <a href="/fileserver/config/" target="_self">config</a> folder on the SD-card gets zipped and provided as a download.</p>

    <button class="button" id="startBackup" type="button" onclick="startBackup()">Create Backup</button>
    <p id=progress></p>
    <hr>
    <h2>Restore Configuration</h2>
    <p>Use the <a href="/fileserver/config/" target="_self">File Server</a> to upload individual files.</p>
</body>


<script type="text/javascript" src="common.js?v=$COMMIT_HASH"></script>
<script type="text/javascript" src="jszip.min.js?v=$COMMIT_HASH"></script>
<script type="text/javascript" src="FileSaver.min.js?v=$COMMIT_HASH"></script>
<script>

function startBackup() {  
    document.getElementById("progress").innerHTML = "Creating backup...<br>\n";
    
    // Get hostname
    try {
        var xhttp = new XMLHttpRequest();
        xhttp.open("GET", getDomainname() + "/info?type=Hostname", false);
        xhttp.send();
        hostname = xhttp.responseText;
    }
    catch(err) {
        setStatus("<span style=\"color: red\">Failed to fetch hostname: " + err.message + "!</span>");
        return;
    }
    
    // get date/time
    var dateTime = new Date().toJSON().slice(0,10) + "_" + new Date().toJSON().slice(11,19).replaceAll(":", "-");
    
    zipFilename = hostname + "_" + dateTime + ".zip";
    console.log(zipFilename);

    // Get files list
    setStatus("Fetching File List...");
    try {
        var xhttp = new XMLHttpRequest();
        xhttp.open("GET", getDomainname() + "/fileserver/config/", false);
        xhttp.send();
        
        var parser = new DOMParser();
        var content = parser.parseFromString(xhttp.responseText, 'text/html');    }
    catch(err) {
        setStatus("Failed to fetch files list: " + err.message);
        return;
    }
    
    const list = content.querySelectorAll("a");
    
    var urls = [];
    
    for (a of list) {
        url = a.getAttribute("href");
        urls.push(getDomainname() + url);
    }
    
    // Pack as zip and download
    try {
        backup(urls, zipFilename);
        }
    catch(err) {
        setStatus("<span style=\"color: red\">Failed to zip files: " + err.message + "!</span>");
        return;
    }
}


function fetchFiles(urls, filesData, index, retry, zipFilename) {
    url = urls[index];

//    console.log(url + " started (" + index + "/" + urls.length + ")");
    if (retry == 0) {
        setStatus("&nbsp;- " + getFilenameFromUrl(urls[index]) + " (" + (index+1) + "/" + urls.length + ")...");
    }
    else {
        setStatus("<span style=\"color: gray\">&nbsp;&nbsp;&nbsp;Retrying (" + retry + ")...</span>");
    }

    const xhr = new XMLHttpRequest();
    xhr.open('GET', url, true);
    xhr.responseType = "blob";

    if (retry == 0) { // Short timeout on first retry
        xhr.timeout = 2000; // time in milliseconds
    }
    else if (retry == 1) { // longer timeout
        xhr.timeout = 5000; // time in milliseconds
    }
    else if (retry == 2) { // longer timeout
        xhr.timeout = 10000; // time in milliseconds
    }
    else if (retry == 3) { // longer timeout
        xhr.timeout = 20000; // time in milliseconds
    }
    else { // very long timeout
        xhr.timeout = 30000; // time in milliseconds
    }

    xhr.onload = () => { // Request finished
        //console.log(url + " done");

        filesData[index] = xhr.response;

        if (index == urls.length - 1) {
            setStatus("Fetched all files");
            generateZipFile(urls, filesData, zipFilename);
            return;
        }
        else { // Next file
            fetchFiles(urls, filesData, index+1, 0, zipFilename);
        }
    };

    xhr.onprogress = (e) => { // XMLHttpRequest progress ... extend timeout
        xhr.timeout = xhr.timeout + 500;
    };

    xhr.onerror = (e) => { // XMLHttpRequest error loading
        console.log("Error on fetching " + url + "!");
        if (retry > 5) {
            setStatus("<span style=\"color: red\">Backup failed, please restart the device and try again!</span>");
        }
        else {
            fetchFiles(urls, filesData, index, retry+1, zipFilename);
        }
    };

    xhr.ontimeout = (e) => { // XMLHttpRequest timed out
        console.log("Timeout on fetching " + url + "!");
        if (retry > 5) {
            setStatus("<span style=\"color: red\">Backup failed, please restart the device and try again!</span>");
        }
        else {
            fetchFiles(urls, filesData, index, retry+1, zipFilename);
        }
    };

    xhr.send(null);
}


function generateZipFile(urls, filesData, zipFilename) {
    setStatus("Creating Zip File...");

    var zip = new JSZip();

    for (var i = 0; i < urls.length; i++) {        
        zip.file(getFilenameFromUrl(urls[i]), filesData[i]);
    }

    zip.generateAsync({type:"blob"})
    .then(function(content) {
        saveAs(content, zipFilename);
    });

    setStatus("Backup completed");
}


const backup = (urls, zipFilename) => {
    if(!urls) return;

    /* Testing */
    /*len = urls.length;
    for (i = 0; i < len - 3; i++) {
        urls.pop();
    }*/

    console.log(urls);

    urlIndex = 0;
    setStatus("Fetching files...");
    fetchFiles(urls, [], 0, 0, zipFilename);
};


function setStatus(status) {
    console.log(status);
    document.getElementById("progress").innerHTML += status + "<br>\n";
}

function getFilenameFromUrl(url) {
    return filename = url.substring(url.lastIndexOf('/')+1);
}

</script>

</html>
